The total value of quarters and dimes in a coin bank is $5.20. If the quarters were dimes and dimes were quarters, the total value of the coins would be $4.60. How many quarters are in the bank?

Respuesta :

Answer:

There are 16 quarters in the bank

Explanations:

Let the number of quarters be represented as q

Let the number of dimes be represented as d

Note that:

1 dime = $0.1

1 quarter = $0.25

The total value of quarters and dimes is $5.20

This can be interpreted mathematically as:

0.1d + 0.25q = 5.20.................(1)

If the quarters were dime and the dime were quarters, the total coins would be $4.60

This means that:

q = d

d = q

0.1q + 0.25d = 4.60

0.25d + 0.1q = 4.60...........(2)

Multiply equation (1) by 25 and equation (2) by 10

2.5d + 6.25q = 130..........(3)

2.5d + q = 46..........(4)

Subtract equation (4) from equation(3)

5.25q = 84

q = 84/5.25

q = 16

Substitute q = 16 into equation (1)

0.1d + 0.25(16) = 5.20

0.1d + 4 = 5.20

0.1d = 5.20 - 4

0.1d = 1.2

d = 1.2 / 0.1

d = 12

Therefore, there are 16 quarters and 12 dimes in the bank